Energy2D

NSF-Funded Free Software

“Please accept our thanks and congratulations for your very interesting work which I am sure are having a great positive impact in our society.”
— from Roberto Quevedo, Instituto Volcanológico de Canarias, INVOLCAN, Puerto de la Cruz, Tenerife, Canary Islands, Spain

By Carmen Trudell, University of Virginia

What is it?

Based on computational physics research ([1], [2], [3]),
Energy2D is an interactive, visual multiphysics simulation program that models all three modes of heat transfer—conduction, convection, and radiation, and their coupling with particle dynamics.
Energy2D runs very quickly on most computers and eliminates the switches among preprocessors, solvers, and postprocessors typically needed to perform computational fluid dynamics simulations.
It allows you to design "computational experiments" to test a scientific hypothesis or solve an engineering problem without resorting to complex mathematics.

In addition to heat transfer, work is also underway to incorporate other types of energy transformations (e.g., phase changes and chemical reactions through
the Stefan condition), to support multiple types of fluids (e.g., air and water),
and to provide sensor interfaces for creating mixed-reality applications.

What is the goal?

The ultimate goal of Energy2D is a versatile computer-aided engineering (CAE) system
for exploring and learning science and engineering through virtual experimentation, investigation, and design.
Therefore, the capability of creating complex, accurate scientific simulations of natural phenonmena and engineering problems is the most important goal of Energy2D.
Realizing that many existing engineering simulation programs are too difficult to use by novices, our main objective is to rethink a CAE
system that empowers, rather than frustrating, the majority of users.

An IR image of a heated model house with a ceiling

An IR image of a heated model house without a ceiling

An Energy2D simulation of a heated house with a ceiling

An Energy2D simulation of a heated house without a ceiling

How well does it model reality?

The conduction part of Energy2D is highly accurate, but the convection and radiation parts are not 100% accurate. Hence, in cases
that involve convection and radiation, Energy2D results should be considered as qualitative.
The pictures to the right show a comparison of the results of Energy2D simulations with images from infrared (IR)
thermography for a simple model house. The thermal patterns predicted by Energy2D roughly match those from an IR camera.

What people are saying about it?

“The software program Energy2D is used to solve the dynamic Fourier heat transfer equations for the Convective Concrete case. Energy2D is a relatively new program (Xie, 2012)
and is not yet widely used as a building performance simulation tool. To gain more confidence in the predictions with Energy2D, an analytical validation study was therefore carried out first,
inspired by the approach described in Hensen and Nakhi (1994). Those analytical solutions and the simulation results of the dynamic response to a 20°C temperature step change on the surface
of a concrete construction with the following properties were compared for this research... the simulation results never divert from the exact solution more than 0.45°C and it is therefore
considered acceptable to further use this model.”
— Dennis de Witte, Marie L. de Klijn-Chevalerias, Roel C.G.M. Loonen, Jan L.M. Hensen, Ulrich Knaack, & Gregor Zimmermann, Journal of Facade Design and Engineering

“Speaking of the thermo-electric analogy being presented in this work, it is worth mentioning the freely downloadable Java app Energy2D, which permits the
numerical/interactive solution of a basically unlimited series of simulations concerning heat transfer. As such, this app can also be seen as an almost perfect and very customizable
numerical engine for treating electrostatic problems of various assortment.”
— from Stefano Oss & Giuliano Zendri, European Journal of Physics

“Thank you for your absolutely great app which helps me a lot for visualizing my lecture in thermodynamics. It is also very nice to see that three platforms are supported
and every single one is free to use. That is just awesome and I want to say thank you for all users. I do not know how many messages of this type you are receiving.”
— from Martin Weise, Austria

“In gearing up to teach a course called Building Science this semester, I somehow stumbled across your program Energy2D and Energy3D. I was really impressed by how simple
and easy these tools were and I'm definitely going to integrate them into some portion of my lectures.”— Prof. Brent Stephens, Department of Civil,
Architectural and Environmental Engineering, Illinois Institute of Technology, USA

“I am currently involved in renewable energy related research activities and teaching. I have downloaded and demonstrating Energy2D for my heat transfer course.
It is really a very useful tool.”— Dr. Mazharul Islam, Department of Mechanical Engineering, Taibah University, Saudi Arabia

“Today during the lunch break a little simulated comparison fan in the suction and blowing operation collector here about 50x70 cm and fan with 2 meters / second. [The result] is
confirmed by the experiences of several users: pressure losses and less volume of air in the blowing operation.”
(Link to the source)

“...what was really interesting, was that when I continued playing with the simulator, sometimes my convection examples would split into two cycling air cells, one above and to the left,
one below and to the right, with the hot air blasting right for the cold source, rather than rising. That's really interesting, because I've experienced this when using smoke demonstrations
in class, and the fact that the simulator can capture that behavior shows how accurate this teaching tool actually is.”
(Link to the source)

“...this free software is basic, yet you can modify properties and all, the desktop download gives better results and the pages have a choice of practical setups to download and use that are very practical”
(Link to the source)

Miscellaneous

The development of this program is funded by the National Science Foundation under grants #0918449 and #1304485.
Any opinions, findings, and conclusions or recommendations expressed in the materials associated with this program
are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.